The present invention relates to a high performance supercavitation centrifugal pump capable of lifting or driving liquids and slurries with or without lumpy solid matters such as ore, soil, sand, gravel, straw, fishes, foodstuffs, flocks, etc. contained in the lifting or driving fluid without damage from such solid matters. The pump generates a high suction pressure and has a powerful gas and vapor expulsion abilities, and is not only free from the cavitation erosion, but also free from the abrasion, damage or destruction caused by solid matters or gases in the lifting or driving fluid.
In the conventional centrifugal pumps, the impeller blades or vanes suffer from severe frictional abrasions by solid matters contained in the liquid, and the discharge port of the pump is frequently clogged by solid matters since the solid matters tangle or cling to the impeller blades or vanes. Furthermore, the impeller blades or vanes are subjected to the severe erosion and vibrations caused by the fixed cavitations even in the aerated liquid containing above 10% of gas, resulting in the sharp decrease of the suction power and finally in the destruction of the impeller.
In the construction of the conventional centrifugal pumps, the volute casing of the pump is provided with a nose portion or whirl point protruded from the inside surface near the discharge port of the casing toward the impeller in order to prevent the lifting fluid from being recycled together with and around the impeller, but said casing has the drawbacks that the solid matters are clung to said nose portion and thus crushed or destroyed, and the pumping efficiency is decreased due to the whirlpool caused by the increasing relative velocity of the liquid and the impeller, and the pump casing and the impeller themselves are damaged due to the collision and friction by the solid matters in the lifting fluid, resulting in the damage and destruction of the solid matters in the liquid. Besides, the conventional centrifugal pumps sometimes require the auxiliary pumps for self-suction in the initial operation stage.
It is therefore an object of the present invention to eliminate such drawbacks so as to provide an improved centrifugal pump, more particularly a powerful supercavitation centrifugal pump for handling agricultural and marine products, for hydraulic conveying systems in the fields of construction works, heavy industries, mining, environmental sanitation, and chemical processess such as agitation, aeration, washing, separation, classification, thickening, mixing, scum breaking, hydraulic dredging, hydraulic excavation, ore dressing, sand trapping, coal dressing, peat handling, fish breeding, sewage treatment, food processing, slug and coke powder treatment, mill scale treatment, dredging of deposited sludge and sand, flock ejecting and conveying, pulp sludge conveying, cattle nightsoil treatment, and emergency draining, etc.